SixtyPical

SixtyPical is a very low-level programming language, similar to 6502 assembly, with static analysis through abstract interpretation.

In practice, this means it catches things like

you forgot to clear carry before adding something to the accumulator
a subroutine that you call trashes a register you thought was preserved
you tried to write the address of something that was not a routine, to a jump vector

and suchlike. It also provides some convenient operations and abstractions based on common machine-language programming idioms, such as

copying values from one register to another (via a third register when there are no underlying instructions that directly support it)
explicit tail calls
indirect subroutine calls

The reference implementation can execute, analyze, and compile SixtyPical programs to 6502 machine code.

SixtyPical is a work in progress. The current released version of SixtyPical is 0.9-PRE (not released yet.)

Documentation

Compare word (constant or memory location) with memory location or pointer. (Maybe?)

And then write a little demo "game" where you can move a block around the screen with the joystick.

To turn word type into byte.

This preserves them, so semantically, they can be used even though they are trashed inside the block.

copy x, [ptr] + y
Maybe even copy [ptra] + y, [ptrb] + y, which can be compiled to indirect LDA then indirect STA!
Check that the buffer being read or written to through pointer, appears in approporiate inputs or outputs set.
initialized byte table memory locations
always analyze before executing or compiling, unless told not to
trash instruction.
interrupt routines.
6502-mnemonic aliases (sec, clc)
other handy aliases (eq for z, etc.)
have copy instruction able to copy a constant to a user-def mem loc, etc.
add absolute addressing in shl/shr, absolute-indexed for add, sub, etc.
check and disallow recursion.
automatic tail-call optimization (could be tricky, w/constraints?)
re-order routines and optimize tail-calls to fallthroughs